Gas bag modules which are integrated in the back rest of a motor vehicle usually include a gas bag and a gas generator. The currently most frequently used gas bags integrated into the back rest are folded in a box shape so as to be as compact as possible. In order to offer an optimum protection for the thorax-, abdominal as well as the pelvic area of the vehicle occupant, it must be ensured by expensive ways and means that the unfolding of the gas bag takes place promptly in upward and downward directions, i.e. in the direction of the extent of the back rest, and also to the front in the direction of travel, i.e, perpendicularly to the extent of the back rest.
By the invention, it is to be ensured that the vehicle occupant is protected promptly and sufficiently by the gas bag, with, at the same time, a small amount of technical expenditure in manufacture and installation of the gas bag module.